The Government's Novopay schools' payroll fiasco has been one of the most stressful elements of the past six months for teachers and support staff, Secondary School Principals' Association president Patrick Walsh says.

Schools appreciated the $6 million the Government had made available to assist them, but it still fell short.

"It's probably become a toxic brand ... they're best to ditch it and go back to Datacom," Mr Walsh said at the 2013 principals' symposium in Queenstown yesterday.

Even if the system could be recovered, as the Government believed, trust and confidence in it may not be, Mr Walsh said.

He questioned whether the Government had done due diligence on a system that it had already spent $30m on, and which was known to have problems in Australia.

"We've had examples of people not paid for three to four months. They've had to negotiate special deals with banks. There have been implications for childcare, ACC, tax and KiwiSaver," he said.

In other cases, schools had advanced money to staff or banks had been very co-operative in supplying interest-free loans, but it should not have been necessary.